Wood flooring



J. F. MCBRIDE WOOD FLOORING Filed Dec. 1, 1937 INVENTOR. BY /ul/ Wwf/(: WM' ATTGRNEYS Feb. 28, 1939.

Patented Feb. 28, 1939 UNITED STATES WOOD FLOORING JamesF. McBride, Arlington, Va., assigner of one-half to Othmar A. Moeller, Orange, Va.

Application December 1, 1937, Serial No. 177,622

6 Claims. (Cl. 20-7) This invention relates to wood flooring and to method for laying it. The invention more particularly is directed to the art of laying parquetry, strip, plank, block, square flooring and the like upon concrete and composition sub-floors and the like.

While it is convenient and economical to lay wooden flooring upon concrete sub-doors Without using screeds 'or sleepers, and while block and parquetry laid in designs in this manner present an unusual and pleasing appearance, this type of flooring construction never has found the exten- V sive uses expected of it because of the great tendency of the flooring to warp, buckle, and become loosened after relatively short periods of usage. For instance, it is typical for such-flooring to remain intact for several months or perhaps a year or more, but thereafter the pieces of flooring either become loose and unjointed during the winter months when the atmosphere in the room is hot and dry, or become warped and buckled during the spring and fall of the year when the humidity is high and the Wood has opportunity to become moist. The ooring then presents an unsightly appearance and must either be renished by scraping and sanding or must be relaid entirely,

'I'he objective of the-present invention has been to provide a method for laying wood block, strip, square, and parquetry flooring over concrete subfloors and the like which will provide an installation remaining intact, tight, and unwarped or buckled during the most adverse moisture conditions and, also, under adverse conditions of usage. More particularly, an objective of the invention has been to provide a better and more satisfactory method for laying such flooring than` -any of the methods which have been available in the past.

40 In modern methods of building construction a steel framework encased in concrete is provided for the building, and sub-floors between the yframing elements are provided also of concrete. In the present specification the concrete floors are termed sub-floors and the wooden flooring which is laid above them is called "finished flooring. The term concrete sub-floors is intended to designate sub-floors of concrete, per se, floors of composition agglomerate, including gypsum and the like, floors of concrete and cinder blocks, and also sub-oors including metal areas. This wood finish licor-ingV may be anywhere from a half an in'ch to an inch and an eighth or more in thickness, and it may be constituted of long strips laid parallel to one another, termed strip flooring, or of short strips of equal length and so coniigurated that a plurality of them may be assembled into the form of a square or geometric figure. Usually the edges and ends of the pieces are provided with respective matching tongues 5A and grooves for joining. In some cases, squares of the flooring may be fabricated and glued at the woodworking plant and then laid on the job in the form of blocks. By varying the directions of grain of such blocks or squares, pleasing eifects ln in the finished flooring are obtained. These effects may be of checker-board design or other- Wise, depending upon the type of flooring laid up on the job to suit individual taste.

In the past the Wood blocks or pieces have l5 been coated, before laying, with a thin coating of tarry substance termed mastic. This mastic is somewhat tacky and adhesive when at room temperature and fluidifiesl when heated. This mastic, of which there are a number of kin-ds 20 sold under different trade names,has been used primarily as an adhesive or glue to position the blocks or pieces in the flooring.v When mastic is used at the present time, the usual procedure is to trowel the mastic by hand yonto a small sec- 25 tion of floor, then lay some flooring, trowel additional mastic, and so on until the area finally is covered. In some instances the mastic is heated to a degree and the individual blocks or pieces of wood are dipped into a shallow pan of 30 the heated substance to provide the coating on the wood. It has been impossible to coat long strips of flooring in this manner, and, in actual practice, it has been found that the method is not satisfactory even for squares and short 35 lengths, because the workmen always'have great reluctance to dip the blocks properly into the pan in view of the danger of burning their iingers with the mastic while holding the blocks.

These methods of laying oors do not provide the type of bond requiredto obtain the desired permanency and stability of installation. After short periods of usage of the floor the bond by which the flooring is held in place is broken, the Wood shrinks, warps, or contracts and becomes 45 so loose that it must be relaid. It is not unusual, as an example, for an entire ioor to become so loosened that individual blocks 'canl either be picked up by hand at the points adjacent the walls, or easily knocked loose from the sub-floor. 50

I have discovered that a primary factor iniluencing failure of the finish ooring lies in the nature of the surface of the concrete sub-licor.

lThe surface of this concrete base is ofthe nature of a lithographie surface. It is receptive to 55 water, but it tends to repel oil and, likewise, to repel oleaginous, mastic substances. 'I'he concept of the-present invention is to convert 'this surface of the concrete into a non-lithographie sur-.- face receptive to, and penetrable by, mastic applied theret in suitable condition. for penetration and reception.

When a mastic is 'disposed on the natural surface of a concrete sub-floor it sets and congeals but does not bond evenly and uniformly. Instead, upon occasion, it actually may be picked f up as an intactT layer just as may be a piece/of diums is retained by the surface for a substantial thetorchmay,beshieldedormaycarryahoodto f period of time after the actual heating operation.

The method of the present invention resides briefly in the treatment of the surface of the subdoor of concrete or the like with heat to ,destroy its lithographie nature, and in the establishment of a mastic .pad or sheet of substantial thickness over the concrete and'bonded to it by virtue of the original treatment.

More Yspecically, the method of the present invention resides in treating the concrete subfloor to destroy the lithographie nature of its surface, and in then 'pouring or applying hot, fluid, mastic on this receptive surface. The fluid mastic next ispermitted to seek its own level,

atleast in local areas overY the floor, and to cool to tacky consistency. Finally the finished floor is laid upon this tacky, mastic pad which thus has been established.

In the practice of the invention, I' have found that the mostconvenient and economical way of treating the surface of concrete or composition sub-floor is to heat it by means of flame from a torch until it exhibits an average temperature,

y after treatment, of about to 90 F. more` or less, depending upon climatic conditions existing atthe time of the installation.

The usual concrete sub-floor is not troweled or smoothed to a line finish during laying. and, consequently, it usually isvery rough and uneven. In the practice of the invention the surface of such a sub-floor is heated by passing over ita torch of the type conventionally used for heating asphalt in road construction work. It desired,

confine the names, though it is preferable to use anopennametopermittheworkmento observe the condition of the concrete as it becomes heated. Ifthe'weatherisverywetandtheooris being laid, for instance, in an apartment buildingonlypartlynnished,andinwhlchthewin dows have not yet been hung, it is preferable to heat the concrete floor .to a temperature of about 90 orso fora-period of time sumcienttodry -upallofthewetareasandacclnnulatedpcolsof water. 'Iheflamesraisethetemperatxneat'the mrfaceportionsmmnentarilyto adegreemuch higherthanw" to 90 1|'. inashort'perlod of time. Durlngsuchheatingtheporesat the surfaceoftheconcreteareopenedandtheconcrete sub-floorisprovidedwithanupperskimorintegument, in relatively 'dehydrated condition i when permitted to st This skin has lost its lithographic character and provides a rm purchase for the mastic pad next applied to it. Y

The neirt` featureof the invention resides in the establishment 'of themastic pad or sheet on the concrete sub-floor by pouring or applying the mastic when and while it is inliquid condition, for instance, at a--temperature of 350 to 400 F. approximately. Sufficient mastic is poured onto the floor to obtain a layer from a sixteenth to three thirty-seconds of an inch or more in thickness. By virtue of the fact that this mastic is in fluid condition when it is applied, it seeks its own level when permitted to stand for a period of time. The top surface thus becomes smooth, even, and uniform, while the mastic at the lower surface has filled in all of\ thecrevices of the rough concrete sub-floor. In this manner the mastic is treated in such a way that it actually penetrates into the dehydrated skin of the 'concrete, fills in the pores, and becomes firmly united therewith. This mastic pad provides a film and stable bond upon which the wood flooring next is laid. Being of substantial thickness, the pad essentially constitutes a continuous unbroken layer of insulation, preventing migration of [moisture from the 'concrete sub-floor into the wood of the finished floor. At the same time, this pad, d for a, period after it has been poured on, see s its own level and provides aa smooth, even, and tacky surface to receive and hold the finished flooring.

Another feature of the invention resides in the use of a pad of substantial thickness. If the floor is very rough and irregular, Vthe uidity of the mastic, when it is applied, enables the provision of a smooth and level surface upon which the finish floor is laid. This pad, therefore, ex-V tends over the entire surface of the room and troweling or smoothing is unnecessary. In ordinary installations it usually is sulcient to pour on a mastic suillciently fluid to seek its own level in relatively local areas, since gradual variations of level over the entire mastic sheet are relatively unimportant.

The wooden finished flooring is laid upon the mastic pad after it has been permitted to cool and become tacky. The workman laying the floor may start at one point, for instance, at the doorway, land then lay block after block, or strip after strip, working from the nished flooring he has already laid toward the unfinished sections. Each piece is laid preferably witbfits tongue fitting into the groove of the piece previously laid. By virtue of the tacky nature of the mastic, only l relatively slightpressure upon the piece is necessary for it to become bonded firmly to the pad beneath it.

A cross-sectional view of a typical flooring construction provided in'accordance with the presf ent invention, is illustrated in the drawing at Figure 1. The finished flooring is indicated generally at 2. The drawing illustrates finished flooring comprised of pieces assembled in the fon of squares, some of which pieces, 3, are laid with the grain running in one direction and other of the pieces, l, with the grain running in Y an alternate direction. The Pieces are tongued and moved for joining, as at s. These pieces of ,atthebasa asat l. Themasticpad or layerof substantial thickness is indicated at l. This mastic pad conforms to the: rough and irregular surface I of the concrete sub-floor l. v.

Figure 2 ofthe drawing illustrates'the con- 110011118. if desired, may be relieved by-groovmg vlo venient method for playing a torch ame upon the concrete sub-floor to destroy the lithographie nature of the sub-floor surface. In this figure the Vtorch is indicated at IIJ. This torch is manipu- 5 lated by a workman and is kept in motion over the surface until the desired treatment is obtained.

The mastic which I prefer to use in the practice of the invention is asphalt or an asphaltic base composition'appropriately uid and viscous when heated to S50-400 F. If desired the fluidity may be adjusted by the incorporation of volatile oil therewith. The'mastic essentially comprises a composition sufficiently fiuidwhen hot to be poured and applied easily and conveniently, and

suiciently tacky when cooled to room temperature to bond firmly with the wood of the finished fiooring. By virtue of the tackiness of the mastic,

it conforms readily to the irregularities or grooving in the under surface of the finished flooring,

so that adhesion takes place over the entire surface of each individual piece of wood. Moreover,

grooving the under faces of the fiooring pieces,

as at 6 of Figure 1, facilitates purchase of the masticron the wood and prevents creeping movel ment of the flooring.

A typical mastic adapted to the practice of the invention comprises a prepared asphalt cement having the following specification:

Minimum Maximum Specific gravity at 60 F 1.050 l 070 Penetration 77 F. 100/5 sec 60 70 Penetration 32 F. 20G/60 sec l5 20 35 Melting point (ring and bau) 115 F. 125 r. Ductility at 77 F 40 cms. Flash point (C. O. C.) 350 F. 450 F. Loss at 325 F. 50 g., 5 hrs 0. 5% 1.5%

Residue after loss, test-penetration 77 F.

100/5, as compared to original penetra- 'tion before heating 60% 40 Bitumen (soluble in CSi) 95% 98% A sh 1.0% 3. 0% Fixed carbon (ash free) 11% 13% Sulphur .v 3.0% 4. 5% Parafne scale (Holde method) 0.5%

5^ The characteristics or specifications, of the mastic may be varied to suit climatic conditions generally existing in the different localities in the country. For example, a mastic `intended. to be used in the southern localities, where the temperature-is relatively high, may have a melting point of about 190 F., while it is preferable that a mastic intended to be used in the northern and eastern seaboard localities have a melting point Vof about 120 F. In cases where the sub-fioor is of a composition high in magnesium chloride,

which is deteriorative to asphalt base mastics, it

is preferable to use one ofthe special base commercial mastic compositions with which those skilled `in the art are familiar. These, likewise, are applied in heated, fluid condition.

If the Weather is very cold when a floor is to be laid, or if the4 sub-floor has become very Wet, as by the bursting of a water pipe or the like during the course of building construction, in

some instances it is desirable to apply a priming coat over the concrete sub-floor after it has been heated and opened. A suitable priming coat coniprises a mastic, such as that disclosed above, diluted or cut back with an amount of oil sufficient to provide a degree of fluidity in the priming coat, enabling it to penetrate the concrete and prevent migration of moisture into'the dehydrated surface before the mastic pad itself can be established.

The typical procedure in layingooring in acl cordance with the present invention is as follows:

The rough sub-oor first is swept clean of any loose dirt, plaster, cement, and dust, then the sub-floor is heated as described, the lithographie 5 nature of the concrete surface is destroyed, the surface portion of the sub-floor is rendered penetrable by the hot mastic, and the sub-floor is ready to receive the pad. Next, hot mastic (or fluid priming coat if necessary) is poured onto 10 the sub-oor by means of an ordinary sprinkling can or the like. The workman, after several trials, finds no difficulty in pouring on an amount of mastic suitable to provide a layer of the desired thickness after the mastic has sought its 1'5 own level. Thereafter the pad is permitted to stand for a period of time until the upper surface of the pad has become smooth and the mastic has set to tacky consistency. This period may be anywhere from two to twelve hours, 20 depending upon climatic conditions. In some circumstance laying the finished flooring may be delayed for a week or so after the pad has been laid. When this occurs, it is desirable to torch lightly over the surface of the pad until it at- 25 tains the desired tacky consistency. Finally the ooring is laid in the manner described, or otherwise, a light coat of asphalt primer applied a few hours before the laying of the finish floor restores the tacky condition. 'Ihe finish flooring prefer- 30 ably is sealed, as soon as possible, after it has been laid, to prevent the entrance of moisture from the exposed upper surface.

Strip ooring is laid, according to the method of the invention, in the same manner that block 35 fiooring is laid. If the strips are warped or have become badly bent they may be tacked into place until a firm bond is established between the ooring and the mastic, by nailing through the strips at suitable intervals, using the carbon steel nails 40 which are available at the present time. 'Ihe nails provide temporary fastening of the wood into position until the bond between the flooring and the pad is set, and later are removed.

The flooring laid in accordance withthe in- 45 vention, in a sense, oats upon the pad and the pad, being of substantial thickness, is sufciently resilient to take up the variations through the expansion and contraction of the wood. Such flooring, laid in accordance with the invention 50 and sealed properly at its exposed surface, does not become warped, buckled, or loose even after the fioor has been sloshed and flooded with water and permitted to stand for several days in this wet condition. A relatively perfect bond takes 55 place between the mastic and the Wood within a few minutes timeand is so strong that it is relatively impossible to pry the wood loose by hand without splitting it. In this manner parquet, Wood block, square, and strip ooring can 50 be laid without 'encountering the diiiculties which have characterized such flooring in the past.

The method of the invention also is `useful vin laying new flooring over old and Worn wooden flooring or wooden sub-flooring. In this instance the mastic is poured over the wooden base floor structure in the same manner as that previously described and the new finish ooring is provided upon the mastic pad thus established. The 70 mastic pad in either instance provides aninsulating layer having sound-proofing qualities*I and also provides a pad sufficiently resilient and plastic to prevent either theA old or the new flooring from squeaking during usage ,75

' Having described my invention, I claim:

1. As a new art, the method of laying a wooden floor comprised of pieces of wood upon a concrete sub-hoor by heating thesurface of the sub-floor until' the pores at the surface of the concrete are open and receptive to an oleaginous mastic, then pouring an oleaginous mastic over the iloor thus treated, in an amount sumcient to provide a mastic pad thereon] of substantial thickness, then permitting said mastic to seek its own level over a period of time and provide a smooth, tacky surface, and then laying the pieces of wood flooring upon the mastic Iwhile' the mastic is of a tacky consistency.

2. A'method of providing a wooden finish floor upon. a sub-floor structure. which method concrete base, which comprises, playing a torch name upon the surface of the base to render the surface portion receptive to an oleaginous mastic, then establishing'a continuous layer of substantial thlckness of mastic composition upon the receptive surface of the concrete base and permltting the mastic composition to seek its own level over a period of time and bond rrnly with the base and set to tacky consistency and then laying wooden flooring. upon the mastic layer.

4. The method of laying a wooden floor upon a concrete base, which comprises, heatingv the sur- CERTIFICATE oF. CORRECTION.

aimons vface portion of the concrete base to a substantial temperature over a relatively short period of time to render the surface portion -of the base receptive to an oleaginous mastic, then priming said surface portion by the application of a fluid mastic composition, then establishing thereon a mastic pad of substantial thickness on said floor and permitting the mastic over a period of time to seek its own level and present a smooth but tacky surface, then laying wooden flooring upon said mastic pad.

5. The method for laying wooden flooring upon a concrete base, which comprises, elevating the surface portion of the concrete baseto a relatively high temperature over a relatively short period of time to render such surface portion receptive to an oleaginous mastic, then priming said surface portion with a fluid oleagi` nous mastic, next establishing a continuous lay er` of mastic composition of substantial thickness upon said flooring thus treated, by the application of a mastic composition suiiciently iluid to seek its own level and become tacky when permitted to stand over a period of time and then applying wooden flooring pieces upon vsaid mastic pad after it has become level and tacky.

6. A method o f providing a wooden-finish floor upon a sub-floor structure, which consists in pouring on the said subiloor a heated oleaginous mastic possessing the capacity to set to tacky condition, and an amount suilicient to provide a mastic pad of substantial thickness on said floor, permitting said mastic over a period' of time to seek its own level, and reach tacky consistency and then positioning and bonding pieces of wooden flooring, on said mastic pad.

JAMES Fc-Mcisnmn February 28, 1.959'.

' JAMES F. HCBRIDE.

It is hereby certified that error appears inthe printed specification of the above numbered pat-ent requiring correction as follows: Page it, second column, line 52, claim 6, for the word. Fand" read in; and that the said Letters- Patent shouldbe-read with this correction thereinA that the same may i conform to the' record of. the case in the Patent Office.

signed m1v sealed this ,lich day of Aprii, A. p. 1959.

(Seal) Henry-Van Arsdale Actingbomznissioner of Patents. 

